SnapPea

Cross-platform SnapPy

a user interface to the SnapPea kernel which runs
on Mac OS X, Linux, and Windows.
SnapPy combines a link editor and 3D graphics
for Dirichlet domains and cusp neighborhoods
with a powerful command-line interface
based on the Python programming language.

SnapPy is already the preferred user interface for SnapPea.
In the not-too-distant future its capabilities should
be a superset of those offered by the older Mac OS X interface
(see below), at which point the older Mac OS X interface
will be retired.

Mac OS X SnapPea

The older SnapPea for Mac OS X,
while still incomplete, supports enough features that you
may find it useful for real work.
Currently supported features include: cusped census,
knot and link entry, drilling and filling,
symmetry group, fundamental group, Dirichlet domain and ortholengths.
The even older SnapPea
also remains available.

SnapPea for Windows

A. C. Manoharan has updated his
SnapPea PC for Windows 7.
It continues to run well on Windows XP too.